GB/T 33308-2016 in English

Determination of free methanol in cosmetics

GB/T 33308-2016 standard specifies the gas chromatography determination method for free methanol in cosmetics, which is applicable to the detection of free methanol in creams, lotions, shampoos and hair sprays. The detection limit of methanol in this standard is 6.0 mg/kg, and the quantitative limit is 20.0 mg/kg.

1. Background and significance of standard formulation

With the rapid development of the cosmetics industry, methanol, as a potential harmful substance, has attracted much attention for its residue in cosmetics. The formulation of this standard aims to standardize the determination method of free methanol in cosmetics, ensure product quality and safety, and provide health protection for consumers.

2. Method Principle and Technology Evolution

3. Experimental reagents and instrument requirements

4. Analysis steps and operating specifications

Direct method (non-hair spray low viscosity cosmetics):

1. Take about 1.0g of sample, dilute to 10mL with 75% ethanol and then measure.
2. Filter the sample solution if necessary.

Distillation method (all kinds of cosmetics):

1. Take about 10g of sample, add water, sodium chloride, defoamer and ethanol, and distill in a boiling water bath.
2. Collect the distillate and dilute to 50mL as the sample solution.

5. Result calculation and data processing

According to the formula:

Where, ω is the mass fraction of methanol in the sample (mg/kg), ρ is the mass concentration of methanol in the test solution (g/L), V is the sample volume (mL), and m is the sample volume (g).

6. Implementation suggestions and precautions

• Laboratory conditions:Ensure the purity of the reagents and use distilled water and ethanol solutions that meet the requirements.
• Instrument calibration: Regularly calibrate the gas chromatograph and mass spectrometer to ensure detection accuracy.
• Sample processing: Strictly follow the standard operating procedures to avoid cross contamination.